DESCRIPTION: (Investigator's abstract) A. SPECIFIC AIMS Develop instrumentation to noninvasively determine the density of arterial blood and hematocrit. 1) To demonstrate the use of the Moens-Kortewig (9)and Bramwell-Hill (10) equations to determine the density of blood, noninvasively. 2) The above calculated blood density value can be used to determine the hematocrit of blood, noninvasively. This research relates to the noninvasive determination of blood density, specific gravity, and hematocrit in a living subject. Blood density is the value of mass/unit volume of the blood in-vivo. Since blood is composed of cells and plasma, the density of whole blood is the composite of the density values of the individual component parts. The hematocrit is the ratio of red blood cell volume to whole blood volume and is an important clinical parameter in current medical practice. It is often expressed as a fraction or a percentage of whole blood volume. In current medical practice, the hematocrit can only be determined by drawing blood from the living subject. The ability to rapidly determine blood density and hematocrit values in critical care situations such as trauma and post surgical recovery will have dramatic impact on patient outcomes, survival rates, and cost of care for those patients. This Phase 1 SBIR Grant will produce a proof-of-concept prototype that utilizes fluid flow and pneumatic principles to determine the density of the blood noninvasively. Once the blood density value is determined, the hematocrit value can be calculated from a linear Y=aX+b relationship between the density and hematocrit values. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE